Digital wireless networks enable end users to receive digital content including video, audio, data, and so forth. Using a mobile terminal, a user may receive digital content over a wireless digital network, e.g. a broadcast or multicast network. Digital content can be transmitted in a cell within a network. A cell may represent a geographical area that may be covered by a transmitter in a communication network. A network may have multiple cells and cells may be adjacent to other cells.
A receiver device, such as a mobile terminal, may receive a program or service in a data or transport stream. The transport stream carries individual elements of the program or service such as the audio and video components of a program or service or data in a software distribution. An elementary stream may carry at least a single program or service, i.e. a subset of the data stream. Typically, the receiver device locates the different components of a particular program or service in a data stream through Program Specific Information (PSI) or Service Information (SI) embedded in the data stream.
Digital Video Broadcasting for Handheld terminals (DVB-H) is an ETSI standard specification for bringing broadcast services to battery-powered handheld receivers [ETSI, “Digital Video Broadcasting (DVB): Transmission Systems for Handheld Terminals,” ETSI standard, EN 302 304 V1.1.1, 2004.]. DVB-H is largely based on the successful DVB-T specification for digital terrestrial television, adding to it a number of features designed to take into account the limited battery life of small handheld devices, and the particular environments in which such receivers typically operate.
To reduce the power consumption in handheld terminals, the service data may be time-sliced (like in DVB-H) and then it is sent into the channel as bursts at a significantly higher bit rate than the bit rate of the audio-visual service. Time-slicing enables a receiver to become inactive to conserve battery power while the receiver is not receiving bursts of a requested service.
To indicate to the receiver when to expect the next burst, the time (delta-t) to the beginning of the next burst is indicated within the burst. Between the bursts, data of the elementary stream is not transmitted, allowing other elementary streams to use the bandwidth.
Time-slicing also supports the possibility to use the receiver to monitor neighboring cells during the off-times (between bursts). By accomplishing the switching of the reception from one transport stream to another during an off period, it is possible to accomplish a quasi-optimum handover decision as well as seamless service handover.
DVB-H also employs additional forward error correction (MPE-FEC) to further improve mobile and indoor reception performance of DVB-T. Time-Slicing and MPE-FEC are implemented in a network element called an Internet Protocol (IP) Encapsulator.
Statistical multiplexing (StatMux) is a type of communication link sharing. In statistical multiplexing, a fixed bandwidth communication channel is divided into several variable bit-rate digital channels. The link sharing is adapted to the instantaneous traffic demands of the data streams that are transferred over each channel. This is an alternative to creating a fixed sharing of a link, such as in general time division multiplexing. Statistical Multiplexing is used in many communication applications to improve the overall performance of communication channels. StatMux can improve the overall performance of communication channels by sharing the network resources between a number of services thereby potentially adversely affecting channel capacity usage, transmission delay, and drop rate. In digital video communication applications in which variable bit rate video is used to enhance the video quality, usage of StatMux can remarkably improve the performance of communication networks. Due to the time-slicing transmission scheme in DVB-H, the implementation of StatMux in DVB-H is significantly different from other applications and has some associated difficulties.
As such, techniques for performing statistical multiplexing in conjunction with time-slicing in a digital broadcast network, such as one that uses Internet Protocol datacasting (IPDC) over DVB-H, would advance the art.